The chemistry building blocks used in industrial polymers, fine chemicals etc. are typically prepared from fossil fuels. However, the use of fossil fuel-based building blocks is not sustainable, and it is therefore necessary to find alternative ways of preparing these building blocks.
Biomass and waste products from processes including biomass contain more oxygen than the products obtained from fossil fuels, and they are therefore not immediately useful in preparing organic chemistry building blocks. One example of a waste product obtained from processing biomass is glycerol, which is a byproduct from biodiesel production. According to Ullmann's Encyclopedia of Industrial Chemicals, the production of glycerol will be six times higher than the demand by 2020. Glycerol is not useful as such as a building block, but if it is reduced to allyl alcohol, it could serve as a building block.
U.S. Pat. No. 8,273,926 concerns a method for converting a polyol to the corresponding olefin by heating with formic acid. One of the polyols tested in this patent is glycerol. The disadvantages of the method include the need of carrying out three formic acid treatment/distillation/cooling to room temperature cycles, the use of an inert atmosphere, and the separation of allyl alcohol from formic acid.
Yi et al., ChemSusChem, 2012, vol. 5, 1401-1404, describe rhenium-catalyzed deoxygenation of glycerol, erythritol, and threitol. The authors also tested (NH4)2MoO4 at 165° C. but were unable to isolate any products. The disadvantage of using rhenium-based catalysts is the high price of the non-abundant metal.
Hills et al., Eur. J. Inorg. Chem., 2013, 3352-3361, tested several molybdenum catalysts bearing rather complex acylpyrazolonate ligands in deoxygenation reactions of 1-phenylethane-1,2-diol and 1,2-cyclooctanediol. They also tested two catalysts without the complex ligand (MoO3 and (NH4)6Mo7O24.4H2O) but were unable to isolate any styrene using the reactive styrene oxide as substrate. Styrene oxide is very different from typical biomass-derived polyols as it is activated in the benzylic position.
DE 102008031828, U.S. Pat. No. 5,616,817, US 2009/054701, EP 0415202, and Suprun et al. (Journal of Molecular Catalysis A, vol. 342, 91-100) all disclose the reduction of polyols using a catalyst that involves a minor amount of molybdenum. However, common to all these documents is that none of them disclose all the reactants being dissolved in the common reaction medium, some of them even concerning gas phase reaction. Furthermore, U.S. Pat. No. 5,616,817 and EP 0415202 describe the reduction of the catalyst with hydrogen prior to reaction, meaning that the catalyst in question in fact contains metallic molybdenum.
Hence, there exists a need for an improved process for reducing biomass and biomass-derived compounds in an efficient and cost-effective manner. Preferably, the process should involve a catalyst that is either already commercially available or is readily prepared from commercially available compounds.